Designed partly to meet a US Navy requirement for a low-cost, low-maintenance fighter to operate from Escort Carriers, the F-5 first flew on July 30, 1959. Development of the F-5 continued even after the Navy withdrew its Escort Carriers, and the aircraft eventually evolved into the light, supersonic "Freedom Fighter," serving US allies during the Cold War and as a supersonic trainer in the US. The second-generation F-5 ("Tiger II") also served US allies, but because it was small and maneuverable like a MiG it was also used by the US military as a training and "aggressor" aircraft, acting as the opposing force during military wargames.